ZNB20 Rohde Schwarz 4 Port Vector Network Analyzer 100 kHz to 20 GHz 3.5 mm Ruggedized Test Ports R&S ZNB20 4-Port Vector Network Analyzer (100 kHz to 20 GHz) The R&S ZNB20 vector network analyzer from Rohde & Schwarz delivers precision microwave measurements from 100 kHz to 20 GHz. With its 4-port configuration and ruggedized 3.5 mm test port connectors, this VNA is ideal for differential device characterization, multi-port component testing and complex RF/microwave